JPH04501296A - fuel injection valve - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] fuel injection valve The present invention is a fuel injection valve equipped with a nozzle body, and the nozzle body has a small bowl-shaped protection. cap is attached and the bottom of the protective cap is in at least one injection opening. It relates to a type having a through opening that opens toward the direction.

Conventional technology Already known fuel injection valve (Federal Republic of Germany Patent Application No. 3540660) In this case, the protective cap has a through opening in the bottom downstream of the injection opening.

The protective cap covers the area of the injection opening or the needle ball provided as the case may be. The aim is to prevent damage to the In addition, the protective cap is attached to the nozzle body. Particles from around the fuel injection valve that rush into the intake pipe are deposited in the area of the injection opening. Narrowing the injection opening, which undesirably reduces the amount of fuel injected and This is to prevent the fuel/air mixture supplied to the engine from becoming depleted.

However, when using known protective caps, it is possible to stop the internal combustion engine and Usually a film-like film is present in the through opening of the protective cap after closing the fuel injector. The fuel evaporates due to insufficient cooling due to the strong heating of the internal combustion engine. in this case , components that boil at lower temperatures of the fuel generally vaporize, whereas at higher temperatures of the fuel The components that boil for the first time remain in the through opening of the protective cap and prevent the operation of the fuel injector. at least one injection opening due to repeated starting and stopping of the internal combustion engine during the switching time; As a result, the injection characteristics deteriorate and the internal combustion engine runs unsmoothly. .

Advantages of invention On the other hand, in the fuel injection valve of the present invention having the features set forth in claim 1, As a point, the protective cap provides protection against contact and prevents build-up of external debris. Not only is this avoided, but also during long operating times of the internal combustion engine Fuel accumulation due to the succession of stages may adversely affect the amount of fuel metered by the fuel injector. It will not reduce it. This ensures the correct operation of the internal combustion engine. be done.

Advantageous constructions of the fuel injection valve according to claim 1 can be achieved by the measures specified in claim 2 et seq. It is possible to create

It is particularly advantageous if the protective cap is made of plastic, so that Drawings that guarantee easy manufacturing Two embodiments of the invention are shown briefly in the drawing and will be explained in detail below. 1st The figure is a sectional view of a first embodiment of a fuel injection valve constructed based on the present invention, and FIG. A sectional view of the second embodiment of the fuel injection valve constructed based on the invention, and FIG. 3 are similar to those in FIG. The fuel injection valve shown in Figure 1 is a cross-sectional view taken along the line ■-■. Fuel described in German Patent Application No. 3710467 for internal combustion engines It almost matches the injection valve and is used for injecting fuel into the intake pipe of an internal combustion engine. Ru. A nozzle body 1 is coupled to a valve casing (not shown), and the nozzle body 1 A valve needle 3 is guided in a guide hole 2 of the valve. The guide hole 2 is the nozzle body l shown in the figure. ends in the rear cavity 5, which has a cylindrical shape in the direction of fuel flow. The valve seat 8 is connected to a valve seat 8 configured as shown in FIG. The space between the valve seat 8 and the nozzle body end face 9 is cylindrical. The transition opening IO extends. The valve needle 3 is circular within the range of the valve seat 8 of the nozzle body l. The seal seat extends into the cylindrical pin 12. Ru. In the closed state of the fuel injection valve, the valve needle is moved by the sealing seat 11 to the valve seat 8. In contrast, when the fuel injection valve is open, the seal seat 11 is in contact with the valve seat 8. and the fuel flows into the transition opening IO. Thin hole plate on end face 9 of nozzle body 15 are closely attached by welding, and the hole plate is connected to the transition opening lO. has at least one injection opening 16 in a matching area serving for fuel metering; The injection opening passes through the hole plate at an angle to the valve longitudinal axis 17, in this case Depending on the type of use, the inclination is such that the fuel jet exiting from the individual injection openings 16 is aligned with the longitudinal axis of the valve. 17 inward, or away from the valve longitudinal axis 17 and outward. be exposed. per unit time when the fuel injector is opened, due to the cross section of the injection opening 16. The amount of fuel injected is specified. The fuel injection valve is opened using an electromagnetic method (not shown). It is done in stone. The injection opening 16 is located between the pin 12 of the valve needle 3 and the wall of the transition opening 10. are arranged in the hole plate 15 so as to start from a ring chamber formed between them, When the fuel injection valve is closed, the cylindrical pin 12 protrudes almost to the hole plate 15. are doing.

A protective cap 20 configured in the shape of a small bowl is inserted into the end portion 4 of the nozzle body. The protective cap partially surrounds the nozzle body l in the axial direction with a cylindrical peripheral wall 21. and into the ring groove 23 of the nozzle body l with the locking step 22 directed inward. It engages to fix the position of the protective cap 20. Bottom 2 of the protective cap 20 4 has a through opening 27 coaxially with respect to the valve longitudinal axis 17, and has a through hole 27 in the radial direction. The stop section 28 of the protective cap extends beyond the hole plate 15. It is in contact with 15. Starting from the stop section 28, the bottom part 24 has a hole plate 15 extending radially inwardly to the through opening 27 at an axial distance from the As a result, a ring-shaped notch 29 is formed between the bottom portion 24 and the hole plate 15. The inner width of the notch is smaller than the diameter of the through opening 27. advantageously The protective cap 20 is manufactured from plastic. Inner width of notch 29 , i.e. the extension in the direction of the valve longitudinal axis 17 is significantly smaller, so that the notch 29 is recessed. It has the shape of a holding plate, which creates a large capillary action at every position of the fuel injector. The fuel generated in the fuel and present in the notch flows out from the through opening 27 based on its own weight. There's nothing to do. In this case, the recess 29 increases starting from the through opening 27. axially tapering or widening with a radial extent of internal combustion engine When the engine and therefore the fuel injector are stopped, the fuel injector is closed and in some cases Therefore, the fuel present in the notch 29 and the through opening 27 is subject to strong heating of the internal combustion engine. In this case, most of the components that evaporated at the low temperature of the fuel are vaporized. On the other hand, the components that evaporated at high temperatures are not heated enough, and the components in the notch 29 moves radially outward by capillary action and deposits on the walls of the stopper section 28; As a result, the area of the through opening 27 and the injection opening 16 of the hole grate 15 is freed from the fuel. has been done.

In the second embodiment of the fuel injection valve shown in FIGS. 2 and 3, the first embodiment of FIG. Parts that are the same as for the example are given the same reference numerals, so that the parts in FIG. The explanation applies. The protective cap 20 of the embodiment of FIG. 2 is similar to the protective cap 20 of the embodiment of FIG. forming an axial spacing between the bottom part 24 and the hole plate 15 for the protective cap; at least one through the bottom part 24 starting from the through opening 27 in the radial direction without The difference is that two notches 31 are provided, and the notches are shaped like slits. It extends in the direction of the cylindrical fit 21. In this case, for example, four notches 31, and these notches are circumferentially aligned with each other as shown in FIG. They have the same spacing, and the inner width of the notch in the circumferential direction varies depending on the fuel injection valve position. The diameter of the through opening 27 is small so as to create a capillary action on the material. ing. In this case, the notch 31 extends while increasing in the radial direction and widens in the lateral direction. Or tapered. Four injection openings 16 are shown in FIG. One cutout 31 is assigned to each opening. Although such a configuration is constrained, or more than four located with respect to the injection opening 16 in a different assignment instead of Even small notches can be created perfectly.

As already mentioned with reference to Figure 1, when stopping the internal combustion engine and fuel injection system, Then, the fuel injection valve closes, and the fuel present in the through opening 27 and the notch 31 is released in the radial direction. The fuel moves outwardly in the notch 31, where the fuel is at least intensified due to capillary action. The heated fuel components remain and the fuel accumulates inside the injection opening 16 and the through opening 27. There's nothing to do.

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Claims (1)

[Claims] 1. A fuel injection valve with a nozzle body, and a small bowl-shaped protective cap on the nozzle body. is installed and the bottom of the protective cap is directed toward at least one injection opening. At least one injection opening in the type with a through opening opened by At least one cutout (29, 31) is provided so that the notch causes capillary action on the ejected fuel. The fuel injection valve is characterized by 2. at least one cutout (29) is open towards the through opening (27); and by the bottom (24) of the protective cap (20) so as to extend radially outwardly. The fuel injection valve according to claim 1, wherein the fuel injection valve is covered. 3. 3. The fuel injection valve according to claim 2, wherein the notch (29) is configured in a ring shape. 4. Starting from the through opening (27), a cutout (29) extends in increasing radial direction. 4. The fuel injection valve according to claim 3, wherein the fuel injection valve is tapered or widened in the axial direction. 5. at least one notch (31) is open towards the through-closure (27); , extending radially outwardly through the bottom (24) in the axial direction. Fuel injection valve as described. 6. Claim 5, wherein the at least one notch (31) is configured in the form of a slit. Fuel injection valve installed. 7. At least one notch (31) starting from the through opening (27) in a radial direction Claim 6, wherein the diameter increases and extends and expands or tapers in the circumferential direction. Fuel injection valve installed. 8. The inner width of at least one notch (29, 31) of the protective cap (20) Any one of claims 1 to 7, wherein the through opening (27) is smaller in diameter than the diameter of the through opening (27). The fuel injection valve according to item 1. 9. 9. The method according to claim 1, wherein the protective cap (20) is made of plastic. The fuel injection valve according to any one of the items above.